Energy efficiency
Building design for a sustainable future
This fact sheet explains how energy efficient design and specification principles can be
incorporated into your next building project and the benefits that can be shared not only by
you, but all Victorians.
What’s included in this fact sheet:
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Why do our buildings need to change?
•
How will improved Energy Efficiency benefit me?
•
What should I consider to enhance Energy Efficiency?
o Building envelope
o Building compliance for residential and commercial buildings
o Internal layout and orientation
o Heating and cooling systems
o Lighting
o Renewable energy generation
o Water heaters
o Clothes drying facility
o Peak demand
•
Where can I find out more?
•
Mandatory Requirements
•
Council’s Best Practice Standard.
Why do our buildings need to change?
Around 40% of the world’s energy resources are used in our buildings – both residential and
commercial. Estimates show that the use of electricity contributes approximately 70% of
Victoria’s total greenhouse gas emissions due to our reliance on brown coal.
Passive design principles including thermal mass, external shading, building orientation,
cross ventilation and better insulation in buildings lead to less reliance on energy hungry
mechanical systems to maintain comfortable internal temperatures. Using renewable energy
further reduces a building’s environmental impact.
Good building design decreases power consumption, saves money and reduces the effects of
climate change. On the other hand, poor building design is uneconomical and contributes to
greenhouse gas emissions.
How will improved Energy Efficiency benefit me?
Whether you are an owner, occupier, builder or property developer, adopting
Environmentally Sustainable Design (ESD) principles in the design and construction of
buildings and renovations can result in marked benefits, both now and in the future.
As an owner/occupier you can expect:
•
lower energy bills due to less reliance on active heating and cooling systems
•
improved living comfort
•
future proofing of your building asset.
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Developers and builders can take advantage of:
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enhanced market appeal to prospective purchasers
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higher investment returns
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a development that meets best practice standards and more importantly, community
expectations.
What can I do to enhance Energy Efficiency?
For both home owners planning a renovation to an existing dwelling and developers
planning to construct multistorey buildings, it is important to ensure that ESD is considered
during the initial scoping stages of a project.
In fact, it is more costly to incorporate sustainability measures after the design process is
complete.
The following information in this fact sheet will help you to identify and address the key
areas of energy efficient building design.
Building envelope
The exterior of a building is often referred to as the ‘building envelope’. The building
envelope ensures that occupants are protected from the elements such as heat, cold, wind
and rain.
To maximise the building envelope’s thermal protective capabilities:
•
Insulate walls, floors and ceilings, exceeding current standards.
•
Draft-proof any gaps around doors, windows and vents including any opening
between the interior and exterior of the building.
•
Consider the use of exposed ‘thermal mass’ of a building to balance a building’s
internal temperatures through heat storage and release.
•
Specify high performance windows.
Internal layout and orientation
To minimise your reliance on mechanical heating and cooling systems, consider the following
design principles:
•
Orient living areas to a northerly aspect or as close to as possible, to take advantage
of passive solar gains during colder months.
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•
The positioning and size of windows impacts on the amount of artificial lighting
required during daylight hours. To maximize light ingress, it is preferable to use clear
glazing. You can use highlight or roof windows to increase lighting levels in buildings
with deep floor plans.
•
Carefully study the location of your project. Is there the chance of overshadowing
from neighbouring buildings? If so, consider how you might overcome any potential
problems through clever window placement or reorienting your building.
•
Try to cluster heated rooms together. Separate rooms with doors and apply internal
insulation to walls adjacent to non-heated rooms. For example, adjoining garages
and storage areas can be just as cold as the temperature outside.
“Thermal mass (e.g. exposed concrete floor) can store and release heat in winter when
exposed to direct sun. In summer, thermal mass can assist with passive cooling by releasing
the stored heat at night through effective means of ventilation (night purging).”
Building compliance for residential and
commercial buildings
How can you be certain that your building
envelope meets best practice energy
efficiency standards?
Before commencing a major renovation or
new construction, a building permit will be
required, confirming compliance with the
Building Code of Australia (BCA).
Residential buildings receive an energy
efficiency rating which is calculated through
tools such as:

FirstRate

Building Energy Rating Scheme (BERS)
Pro

Accurate
The rating reflects a dwelling’s energy
efficiency and is measured on a scale of 1 to
10 Stars. A 1 Star rating means that the
dwelling is extremely inefficient and ‘energy
hungry’. While a 10 Star rated building is
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extremely energy efficient and requires very little or no energy for heating and cooling due
to the passive design principles incorporated during the building’s early design stages.
Similarly, non-residential buildings must also meet the BCA’s energy efficiency standards.
However, this is determined using different modelling tools that rate the relative energy
efficiencies of a building.
It’s important to be aware that the BCA only describes minimum standards that must be met
and not what is considered best practice. To ensure you future proof your asset, it is strongly
recommended that you exceed today’s minimum standards.
Energy efficient office buildings are generally rated above 4 Stars under the National
Australian Built Environment Rating System (NABERS).This also makes sure your property
will remain a ‘good performer’ as the standards will be raised over time and that you are
ready for the recently introduced mandatory disclosure scheme.
Heating and cooling systems
Choosing the correct heating and / or cooling system for your project can have a big impact
on your energy consumption and greenhouse gas emissions.
Smart buildings and renovations, will incorporate passive solar design in their construction.
This may include above standard insulation, external shading that can be adjusted to
changing climate conditions, good cross ventilation and the best possible building
orientation.
When all of these are combined, buildings will have significantly lower heating requirements
in winter and you may be able to avoid the need for active cooling systems in summer.
When choosing an active heating and cooling system (reliant on energy to power), be aware
that each has its pros and its cons. Some general rules apply:
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Gas fuelled systems create considerably less carbon emissions than electricity fuelled
systems.
•
The efficiency of a heating and cooling system is rated in stars. The higher the star
rating, the more efficient the unit.
•
Hydronic heating systems (run by hot water) can utilise the sun’s renewable energy
in the form of a ‘solar-boosted’ heating system, that works just like the solar hot
water system on your roof.
•
Central systems in larger commercial developments are generally more energy
efficient. However, individual systems are more flexible and can be easily modified to
suit a building’s changing occupancy.
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Some systems are inherently more efficient than others. A ceiling fan, for example,
will always consume less energy than an efficient air-conditioner.
Building Service’s Energy Efficiency
Building Services
Low Efficiency
High Efficiency
Space Heating
Electric Heating Panels
Gas Boosted
Solar Hydronic Heating
Space Cooling
Electric Air Conditioning
Ceiling Fan
Water Heating
Electric Storage Heater
Gas Boosted
Solar Hot Water
(Solar contribution >80%)
Artificial Lighting
Halogen Light Bulb
Light-Emitting Diode (LED),
Compact Fluorescent
Lighting
When considering artificial lighting design, weigh up these design options:
•
Ensure living areas, including kitchen and bedrooms, do not require any artificial
lighting throughout the day.
•
Familiarise yourself with appropriate lighting requirements (how bright is bright
enough?) for different living and working spaces.
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Choose energy efficient lights and lamps.
•
Install efficient lighting controls such as motion, sound and daylight sensors and time
switches, or a ‘master switch’ that controls several lights, and possibly appliances, at
once.
Renewable energy generation
In addition to good “green” design and performance, many buildings are now being designed
to generate their own energy to supplement or meet everyday’s energy consumption.
Council supports these initiatives and recommends exploring onsite renewable energy
production. Renewable energy options include photovoltaic solar panels and small wind
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turbines for electricity production, solar hot-water heating systems, and geothermal systems
for space heating and cooling.
Solar hot water systems are the most common systems that work with renewable energy free energy from the sun.
“While we weren’t able to provide renewable energy for all 150 apartments, we at least
covered all common area electricity demand (lighting and ventilation for entrance lobby,
corridors and basement) through onsite electricity generation with photovoltaic panels. That
way we not only reduce the development’s environmental footprint but also reduce the body
corporate fees.”
Water heaters
On average, hot water heating contributes 20 per cent of a household’s energy bill. Choosing
a highly efficient system reduces energy costs and a building’s environmental footprint.
Water heaters follow similar guidelines to heating and cooling devices:
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Gas fuelled systems are commonly more efficient than electricity fuelled systems.
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The efficiency of a hot water system is rated in stars. The more the better.
•
A solar hot water system provides a large proportion of the energy required to heat
water by directly using the sun’s energy. Where possible, supplement outstanding
energy requirements using a gas booster, known as a gas boosted solar hot water
system.
•
Instantaneous systems are generally more efficient than storage systems as there is
no water being stored and constantly reheated. However, this can vary, depending
on the fuel source, be it renewable energy, electricity or gas.
Clothes drying facility
A well designed residential dwelling should incorporate natural clothes drying facilities.
External drying spaces give the occupant the opportunity to use sun and wind to dry clothes
rather than electrical appliances. Apartment buildings could provide retractable drying racks
on individual balconies or a common clothes line on the building’s roof terrace.
Reducing peak demand
Peak energy demand refers to the use of electricity, caused by extreme weather events such
as heat waves and cold snaps. For example, on a hot summers day, the Victorian electricity
grid carries an additional load of up to 20% due to the additional use of air conditioners.
Extreme conditions occur on a relatively few number of days per year however this peak
demand is enough to increase demand for the construction of new power stations.
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The impact on consumers is additional costs for the entire year as Victoria’s energy grid is
20% larger than it would need to be without peak demand.
However, we can all take steps to help reduce peak demand on our electricity supplies by:
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installing efficient shading
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providing good insulation
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only using high efficiency heating and cooling systems, which means that specified
systems should be within 1 Star of the highest rating available
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installing photovoltaic panels that produce energy when it is needed most - on a hot
summers day.
Mandatory Requirements and Council’s Best Practice Standard
Environmental Sustainable Design (ESD) Principles
There are two levels of compliance when it comes to ESD principles – mandatory and best
practice.
Mandatory Requirements
Your building or extension meets BCA Energy Efficiency requirements. These requirements
are the minimum standards but are not best practice standards.
Council’s Best Practice Standard
To achieve best practice building standards, as many as possible of the following ESD
principles should be incorporated into a new building or extension design:
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Install appropriate external shading devices responding to different façade
orientations.
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Demonstrate energy efficiencies beyond minimum BCA compliance benchmarks (e.g.
+10% or + 1 Star).
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For office buildings, include a NABERS Energy Commitment Agreement.
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Ensure habitable rooms do not rely on artificial lighting throughout the day.
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Install energy efficient artificial lighting, including sensible lighting controls.
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Provide external clothes drying facilities.
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Consider renewable energy production for a proportion of water heating, space
heating and electricity demands.
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Specify energy efficient (high star rating) heating and cooling systems.
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Install energy efficient (high star rating) hot water systems.
Developments, which seek to vary from these best practice standards, must demonstrate
how energy efficiency can be satisfactorily achieved.
Where can I find out more?
6 Star Energy Efficiency Requirements Building Commission Victoria
www.buildingcommission.com.au
Find an accredited Thermal Performance Assessor Association of Building Sustainability
Assessors www.absa.net.au
Building Designers Association Victoria www.bdav.org.au
National Australian Built Environment Rating System (NABERS) www.nabers.com.au
Choose an Energy Efficient Appliance Department of Climate Change and Energy Efficiency
www.energyrating.gov.au
Renewable Energy System Rebates Sustainability Victoria www.resourcesmart.vic.gov.au
Energy Use Technical Manual Your Home www.yourhome.gov.au
Other Fact Sheets in this series are also available to provide guidance on the 10 Key
Sustainable Building Categories. For further information on Energy Efficiency, see the Fact
Sheets entitled:
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Indoor Environment Quality
•
Urban Ecology
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Building Materials.
This fact sheet is not designed to replace project specific advice from building design and
sustainability professionals, Council does not take responsibility for any issues that may
occur due to the facts and guidance provided in this fact sheet.
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